1. Field of the Invention
The present invention relates to a backlight display module, and more particularly to a sectional dynamic-driving backlight module and a head-up display device thereof.
2. Description of the Prior Art
Recently, assisting devices for increasing vehicle reliability and driver visibility are getting more and more popular base on the driving safety and environment concerns. For instance, global positioning system (GPS) and head-up display (HUD) are commonly applied in automobiles for driving-assist purpose. The HUD is able to project the imaged to be displayed onto a windscreen of the automobile for providing some road-related information to the driver, such as dashboard information and navigation information. By the assist of the HUD, the driver can focus his sight on the front without looking down at the dashboard or turning to staring at the navigation device; and that can prevent driver's attention from being dispersed.
Please refer to FIG. 1, which illustrates a schematic application diagram of a conventional head-up device. As shown in FIG. 1, the conventional head-up device 82′ is install in a vehicle 80′, and includes a backlight module 821′ and a non-self-emitting luminescence display 822′. The backlight module 821′ (such as a light-emitting diode (LED) array) is configured for emitting light and providing a backlight to the non-self-emitting luminescence display 822′ (such as a liquid crystal display (LCD)); therefore, by the LCD, a display image would be projected to an eyebox 84′ of the driver on the windscreen of the vehicle 80′.
Because the backlight module 821′ of the head-up device 82′ emits light divergently, the driver may see the display image on the eyebox 84′ form various visible angle; however, the divergent light causes the shortcoming of low brightness and low light intensity on the display image. For above reasons, the number of the light source must be increased in order to enhance the brightness and intensity of the display image projected by the head-up device 82′. Although the increase of the light source number would enhance the brightness and intensity of the display image, that would also increase the total weight of the head-up device 82′, the usage of electricity and the load of heat-dissipation requirement.
Thus, according to the backlight module 821′ and the non-self-emitting luminescence display 822′ of the head-up device 82′ have many shortcomings and drawbacks, head-up device manufacturers propose a new backlight display module. Please refer to FIG. 2, there is shown a framework view of the new backlight display module. As shown in FIG. 2, the backlight display module 1′ consists of a LCD 100′, a plurality of light sources 110′ and a micro-optical array group 120′. The light sources 110′ (such as LED chips) are disposed at one side of the LCD 100′ for emitting light to the LCD 100′.
The micro-optical array group 120′ is disposed between the LCD 100′ and the light sources 110′ and consisted of a substrate 121′, a period-variable 2D free-form surface lens array 122′ and a period-variable 2D free-form cone array 123′. The period-variable 2D free-form surface lens array 122′ is disposed on one surface of the substrate 121′ and faces to the light sources 110′, used for converging the divergence angle of the light emitted from the light source 110′. Opposite to the period-variable 2D free-form surface lens array 122′, the period-variable 2D free-form cone array 123′ is disposed on the other surface of the substrate 121′ and faces to the LCD 100′, used for directing and focusing the light to an eyebox 130′ of a driver. As the solid line path in the FIG. 2 shows, after the light sources 110′ emits the light into the micro-optical array group 120′, the light path would be adjusted and deflected by the micro-optical array group 120′, and then be concentrated within the eyebox 130′. Moreover, the dotted line path 150 in FIG. 2 further reveals that the light of each of the pixels on the LCD 100′ distribute to and form a cone shape, that means each of the pixels on the LCD 100′ can merely be seen by the driver from the eyebox 130′.
Therefore, through above descriptions, it is able to know that the shortcoming of the head-up device 82′ of FIG. 1 can be solved through replacing the backlight module 821′ and the non-self-emitting luminescence display 822′ by the backlight display module 1′ of FIG. 2. However, it still can find that the backlight display module 1′ includes some shortcomings and drawbacks of:    (1) Although the micro-optical array group 120′ of the backlight display module 1′ is able to converge the divergence angle of the light emitted from the light source 110′ and direct the light to the driver's eyebox 130′, the light does not be homogenized; so that, the non-homogenized light cannot provide a uniform backlight to the LCD 100′, so as to produce an optical dark area and an optical bright area on the LCD 100′; Predictably, it is difficult for the driver to clearly see and effectively distinguish the images or texts displayed on the optical bright area.    (2) The backlight module 1′ cannot project a full-color image to the eyebox 130′ because each of the light sources 110′ are a monochrome LED chip.    (3) Inheriting to above point 2, for making the backlight display module 1′ able to show the full-color display, a color filter must be applied into the backlight display module 1′ and the monochrome LED chips must be the white LED chips. However, the application of the color filter would increase the manufacturing cost of the backlight display module 1′; besides, the white LED chips kept on a continuation-emitting state would also result in high power consumption, and cause the backlight display module 1′ needs to be recurrently charged.
Accordingly, in view of the conventional backlight display module and head-up device still have the drawback of cannot to be incinerated by the incinerator, the inventor of the present application has made great efforts to make inventive research thereon and eventually provided a sectional dynamic-driving backlight module and a head-up display device thereof.